rts_cudaCufftShift.h
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#ifndef CUDA_CUFFT_SHIFT_H
#define CUDA_CUFFT_SHIFT_H
#define BLOCK_SIZE 16
__global__ void devCufftShift(char* gpuSource, int sE, int sX, int sY, int sZ)
{
int ix = blockIdx.x * blockDim.x + threadIdx.x;
int blocks_per_slice = sY/blockDim.y + 1;
int iy = (blockIdx.y % blocks_per_slice)*blockDim.y + threadIdx.y;
int iz = blockIdx.y/blocks_per_slice;
if(ix >= sX || iy >= sY || iz >= sZ/2)
return;
//array index
int i = iz*sX*sY*sE + iy*sX*sE + ix*sE;
int iSwap = (iz + sZ/2)*sX*sY*sE;
if(iy < sY/2)
iSwap += (iy + sY/2)*sX*sE;
else
iSwap += (iy - sY/2)*sX*sE;
if(ix < sX/2)
iSwap += (ix + sX/2)*sE;
else
iSwap += (ix - sX/2)*sE;
//iSwap = (iz + sZ/2)*sX*sY*sE + (iy + sY/2)*sX*sE + (ix + sX/2)*sE;
char temp;
for(int e=0; e<sE; e++)
{
temp = gpuSource[i + e];
gpuSource[i + e] = gpuSource[iSwap + e];
gpuSource[iSwap + e] = temp;
}
}
void rts_cudaCufftShift(char* gpuSource, int elementSize, int sX, int sY, int sZ)
{
//This function duplicates the Matlab fftshift function, making it easier to apply certain filters in
//the frequency domain.
//currently only usable for even numbers
if(sX%2 != 0 || sY%2 != 0 || sZ%2 != 0)
{
printf("Error: cudaCufftShift dimensions must be even (for now)\n");
exit(1);
}
dim3 block(BLOCK_SIZE, BLOCK_SIZE);
dim3 grid(sX/block.x + 1, (sY/block.y + 1)* sZ);
//call the kernel
devCufftShift<<<grid, block>>>(gpuSource, elementSize, sX, sY, sZ);
}
#endif